History isn't discontinuous or quantized, it's a continuous process, and characterized in a lot of cases by flows: migration, agriculture, religion etc. etc.

Talking about different kinds of visualizations gets me to thinking about the power of a synoptic view--merge lots of different data sets, and insights will emerge. An environmental map over 30,000 years merged with a map of migration patterns merged with population density...and on and on...and you'd have to get a deeper insight into how it all connects. I think that flows would emerge clearly, and also "standing waves", like when people began settling in one place for a while...which reminds me to add trade routes to the map starting about 10,000 years back, because those should show currents and eddies and pools that are significant.

We're really still the proverbial blind men and the elephant, trying to understand our past from fragmentary evidence, and of course history isn't getting any younger. I think the dynamic view in these visualizations works with the human mind's ability to fill in the blanks by recognizing the patterns. We'll never have a precise day-by-day account of all our history, but we don't need it if we understand the larger pattern. The pattern's fractal, and the details fill in by self-similarity. The more things change...